I have traveled internationally with my mobile phone, but have always kept the SIM card from my US carrier (AT&T). As a result, I try to minimize my airtime when abroad: no phone calls, use WiFi whenever possible, etc. I am planning several, more extended, trips and am considering getting a local prepaid SIM when I arrive in Stockholm. I have an unlocked iPhone 6, so the SIM is removable. When I return to the US, I'll put my AT&T SIM back in, and keep the Swedish SIM for future travel. I'm aware that some prepaid plans are terminated after a period of inactivity.

I will not have a fixed address in Europe, but I will have credit cards that can be used in Europe.

I've looked at some of the related questions, but they all assume that one knows what they're doing... I don't!

I've never done this before; is this a complicated procedure -- or is what I've described even possible?

Will this cause any issues for my US carrier (e.g., will they terminate my plan)? Obviously, I expect to be billed for my normal monthly plan.

Although I am primarily interested in data, will I be assigned a Swedish phone number for local calls and SMS if needed?

I assume that if someone calls/texts my US number, it will be the same as if the phone was turned off, and I'll get voicemail/texts when I return.

Followup:

I was able to purchase and use a prepaid SIM from Telia.se in my iPhone with minimal problems. I was assigned a Swedish mobile phone number, was able to make and receive phone calls, send and receive text messages, and access the internet.

Since I don't have a personnummer, I was unable to place international calls. This (mostly) wasn't a problem for me, since the whole point of the SIM was for in-country use. The only issue I had was that I was unable to call an International Freephone number from my mobile (which make sense, I guess).

The first of your bulleted items is the real question, which I don't know how to answer. But for the rest: (2) No, your home carrier cannot distinguish between you using a different SIM or simply choosing to turn off your phone for a few weeks/months. (3) There are data-only plans on the Swedish market that look like they don't come with a phone number. They are often used with, e.g., tablets that don't have voice phone functionality. (4) Yes; see (2).
– Henning MakholmAug 22 '18 at 12:56

something to consider as an alternative: T-mobile USA has an unlimited national and international data plan, for a quite normal price. I have been using it for several years, without problems, in India, Russia, Peru, and over a dozen EU countries (including Sweden).
– AganjuAug 22 '18 at 14:34

An other way, get a phone with the option of two sim cards and you can keep your US number active for incoming calls and texts, but use your second sim for all the rest. (Pity iPhones do not yet have the option for a second sim.)
– Willeke♦Aug 22 '18 at 16:31

@HenningMakholm Im not entirely sure about Sweden but for technical reasons data plan only should have an assigned phone number, you just don't know it. Most LTE modems for example are capable of sending/receiving SMSes and USSD.
– Jan DorniakAug 22 '18 at 18:37

1

@JanDorniak: I can imagine that there might need to be an identifying phone number for protocol reasons. But presumably the provider could still refuse to connect calls and SMSes made to/from such a number.
– Henning MakholmAug 22 '18 at 18:46

5 Answers
5

Nothing complicated about it. You buy a prepaid SIM card, maybe get some vouchers to extend the validity and get more voice/data, turn off your phone, switch SIM cards, and reboot your phone. Voilà, you have a Swedish number. Meanwhile, if people call or SMS you on your US number, they won't be able to reach you. Your provider will bill your plan as usual, and that's about it. When you go back to the US you might get a bunch of SMS and missed call alerts.

Depending on the European supplier, you might be able to extend the validity of your prepaid card with recharges.

That's good to know, thanks! So there isn't an issue with not having a local address? I was under the impression that some countries (Germany?) had such a requirement.
– Mike HarrisAug 22 '18 at 13:33

1

I have never bought a German SIM card. With EU roaming regulations, you can buy a card in one country, and use it within the EU for the same cost.
– user67108Aug 22 '18 at 14:00

8

In Germany (everywhere in the EU?) they will ask for an ID (and as non-EU citizen you will have to show your passport) but that's about it. There is no requirement for residency to get a SIM
– Sebastian J.Aug 22 '18 at 14:49

2

A while back (2009) I was required give an address for activating the SIM when traveling in Germany. They didn't actually care if I lived at the address though, so I just gave them the address of a friend that lived there. I suspect if you were ever asked, giving the address of the place where you were staying would be sufficient. Since then, I got a SIM card in the Netherlands twice, and I was not asked for an address either time.
– Kevin PeterAug 22 '18 at 16:53

1

Note that depending on the US provider, you may be able to suspend your account for extended travel.
– chrylisAug 22 '18 at 20:00

You'll also have to check that your phone isn't network-locked. If you're paying for your phone as part of your monthly cell payments, then it might be. A network-lock (sometimes called a SIM-lock) prevents your phone from registering (being used) on another cell network.

The easiest way to check (apart from asking your cell company), is to put a pay-as-you go SIM from another network in it (or even use a friend's SIM). If the phone is network-locked, then the SIM won't work.

If it is locked, then you can ask your cell company to remove the network lock.

Yes, this is possible. I do this with my unlocked US iPhone (at&t) whenever I travel to my birth country in Europe.

On the plane I switch the SIM cards. After arrival I add a small amount of money (~$10) to the EU prepaid SIM card. From that company, I almost immediately get texts with special offers, for example, for $X get a certain amount of minutes, texts and data, and almost always the deal is very good.

Soon after that, a screen pops up asking if I want to make the new number the principal one (no!), and whether I want to add the new number to iMessages and FaceTime (yes!)

I make this trip every few months, which keeps the prepaid card number always active.

On the plane ride back, I put the at&t card back in, and all goes back as it was pre-travel.

You can also get a 2 SIM card phone, or travel with a separate unlocked phone for use abroad. The latter was what I did before I started purchasing unlocked iPhones.

An annoying problem when removing your home SIM us that you won't get important messages.

I had two such issues, both credit card related:

I was notified by SMS that I reached 90% of my credit limit (long trip, lots of expenses). I didn't see it, and when it reached 100% the card stopped working.

When buying online, my card issuer wanted extra authentication by sending me an SMS with a code. So I quickly put my home SIM back in to get it. But try doing this when buying using your local SIM data connection...

A dual SIM phone is the best solution. A cheap GSM phone for your home SIM is also an option.

I'm not sure about the technical aspects of the whole US iPhone vs European SIM. My experience is with a European Android phone and a SIM from a different European country. So you might want to run this past AT&T before you leave.

However:

Is this a complicated procedure?

Not at all. I found it easy: power off my phone, take out the SIM, put the other SIM in, and turn the phone on again. And it didn't break anything when I switched back to my home SIM.

Will this cause any issues for my US carrier?

Don't know specifically about your carrier, but my home carrier didn't terminate my plan even after weeks of using the other SIM. And yes, I was billed by my home carrier on the normal monthly schedule. However, some carriers do deactivate prepaid accounts after longish period of inactivity (6 months?), so this might make your plan to save the Stockholm card pointless.

Will I be assigned a Swedish phone number for local calls and SMS if needed?

Yes. Make sure you have your contacts in the phone memory, not on your home SIM. You can tell your friends this new (temporary) number so they can call/text you. You might also get texts from the Swedish carrier in Swedish, welcoming you as a new customer and so on.

I assume that if someone calls/texts my US number, it will be the same as if the phone was turned off, and I'll get voicemail/texts when I return.

I don't know about voicemails but found my carrier only retained the texts for a while. I got the impression that after ~30 days they expired off my home carrier's system.

Not sure about 6 months, but my daughter's US phone number remained OK for 5+ months while she was in Spain. If you keep paying, it stays alive. One thing to consider is connecting/texting through Google Hangouts rather than a specific phone number. That way it doesn't matter which phone number is active at the time.
– Jon CusterAug 22 '18 at 23:24